Superheat-gage.



T. M. LOTHROP & G. D. BRADSHAW.

SUPERHEAT GAGE.

APPLICATION FILED JUNE 6, 1907.

Patented Dec. 14, 1909.

T. M. LOTHROP z G. D. BRADSHAW.

' V SUPERHEAT GAGE.

APPLIOATION FILED JUNE s, 1907.

943,260. Patent-.ea Dec. 14,1909.

. t 2 SHEETS-SHEET 2.

f3] v Y E?? UNITED sTATEs PATENT OFFICE-,

THOMAS M. LQTHROP AND GRANT D. BRAJ-DSHAW, 0F JOLIET, ILLINOIS.`

SUPERHEAT-GAGE.

Specification of Letters Patent.

Patented Dee. 14, 1909.

Application med .rune e, 1907. seria1No.'a77,49s.

To all whom 'it 'may concern:

Be it known that we, THOMAS M. LoTHRoi and GRANT D. BRADsHAw, citizens of the United States,l residing at Joliet, in the county of IVill and State of Illinois, have invented certain new and useful Improve-I heat gage embodying our invention applied' to the steam .chamber of a superheater to measure and record the varying amount of superheat existing throughout a certain period of time. It 1s well known that the temperature of the saturation point of steam varies in the same direction as the pressure, rising as the pressure increases'and falling as the pressure decreases, so that a pressureactuated indicator working over a scale or dial properly calibrated for temperatures would show the saturation temperature at the existing pressure. An ordinary therT mometer would indicate the absolute temperature. The di'erence between the readings would be the amount of super-heat. In the present invention the indicating mechanism is so designed'as to be acted upon opposite-ly by pressure and temperature so that the resultant movement will represent the superheat alone.

In the accompanying drawings forming part of the specification, Figure 1 is a front elevation of a superheat gage embodying the invention, shown partly broken away; Fig. 2 is a plan view of the pointer and the lever mechanism on an enlarged scale, showing the frame or casing partly broken away; Fig. 3 is a cross section on the irregular line 3 3 of Fig. 1; Fig. 4 is a detail of one of the parallel-motion links and slides in section on line 4 4 of Fig. 2, and Fig. 5 is a detail of one of the pivot-clamps adjustable in the slotted lever.

In the drawings A represents a suitable casing or frame to inclose and support the operative parts ofthe gage. Passing through the bottom of the casing is a plug 2 having Aports 3 and 4 extending longitudinally through it. The port 3 isshown'annular in shape, so as to surround the port 4, and

lmaintain the temperature therein. The plug is made, preferably, with a threaded outer or lower end so that it may be screw-fitted into the shell 5 of a chamber for superheated steam.`

Fitted within vthe lower end of the central port 4 is an outwardly projecting tube or bulb 6 closing the port to communication with the steam chamber, and containing mercury, air or any other expansible Huid 7. Fitting into the upper or'gage ends of the ports 3 and 4 are coil spring tubes P and T, respectively, closed at their outeror free ends and both arranged, preferably, in the same vertical plane. The free ends of these tubes Pv and T are pivotally connected through the medium of links 8 and 8a, respectively, with the clamp bolts 9 and 9a, which are adjustable lengthwise in the slot- `ted arms 10 and 10a of the levers 11 and 11a,

respectively. The bolts are secured in adjusted positions by means of nuts 12 and 12a, which pinch the slotted arms |10 and 10a against the shoulders13 and 13a of the bolts, the bolt-portionabove the shoulder serving as a pivot for the link to work upon. The bolts are made adjustable in the slotted levers in order to regulate t-he movement of the pointer'20 for purposes of calibration. It will be observed that the spring tubes are connected with the lever arms 10 and 10a on opposite sides thereof so that the levers will be oppositely acted upon by the expanding of their respective tubes.

The levers 11 and 11a are fulcrumed upon posts 14 and 14a, p respectively, supported upon the rear wall 15 of the casing. Their acting ends are pivotally connected at 16 and 16a with the links 18 and 18a, respectively. At their other ends these links are pivotally connected with pivot pins 19 and 19a which have slidingsupport in the parallel guides 0r slides 17 and 17a.- The sliding pins 19 and 19a are connectedfwith each other `and with the pointer 20 by the parallel motion system of linkage shown in Fig. 2, whereby the resultant, only, of the movements of the tube actuated levers will be communicated to the pointer, as will be hereafter explained. This linkage comprises two links 21 and 22, preferably of equal length, pivotally connected with the sliding pin 19; a link 23, parallel with 21 and preferably double its length, pivotally connected at one end with the end of link 22 and at the other end with the sliding pin 19a; a link 24, parallel with 22, pivotally connected at one end with the end of link 21 and at the other end, by pivot 25, with the link 23, (preferably at the middle point thereof); and, lastly, a linky 26 pivotally connected at one end, by pivot 27 with the link 24, (preferably at the middle point thereof), and at the other end with the pointer 20. Thus the links 21, 22, 24 and the adjacent portion of link 23 form a paral lelogram, which, when the links are of equal length as shown, will be either a square or a rhomb according to the relative positions of the sliding pins 19 and 19a. 1n any case the pivot 27 will always lie in the straight line connecting the sliding pins 19 and 19a.

The pointer 20 is pivotally' supported upon a post 28 carried by the web 29 of the casing, and its lower end is counter-weighted at 30 to balance the weight of the long indicating end and the connected moving parts. The outer end of the pointer carries a marker 31 which works over the face of a dial moved by clock work and graduated in one direction fortime periods and in the other direction for degrees of superheat. In the drawings is shown a rotary dial B secured to the hour hand arbor 32 of clock work mechanism C supported'within the casing. The pointerA and dial are so positioned with respect to each other that the arc of the circle described by the end of the pointer will pass through the center of the dial. The dial is shown graduated with concentric circles 33 calibrated for degrees of superheat and with radial lines 34 following the curve described by the end of the pointer for indicating the hours of the day. The dial may be covered by a glass plate 35 carried by the casing.

ln operation, the pressure of the steam entering through the port 3 into the tube -P will exert upon the tube an expanding or straightening force, so that upon any increase in pressure the tube will expand, and, acting through the link 8, lever 11, and link 1S, will push the pivot-pin 19 toward the pointer. Upon any decrease in pressure on the other hand, the tube will contract under the influence of its own resiliency, and, acting through the medium of the links and lever just mentioned, will pull the pivot-pin 19 away from the pointer. Similarly, the fluid within the bulb 6 will expand as the temperature of the steam rises and compress the air or other gas in the tube T, and

thereby cause the tube to expand against its own resiliency, as in the case of tube P. 1n thus expanding or straightening, the tube, acting through link 8a, lever 11a and link 18a, will move the pivot-pin 19a; but beingl connected with its lever oppositely from tube P, it will -in expanding draw the pivotpin' away from the pointer vinstead of push so as to indicate an increase in superheat. Conversely, if the temperature remains constant and the pressure increases, the pin 19 will be forced up toward the pointer and the linkage will turn on 19a, which remains stationary, as a pivot, forcing the pointer up toward the center of the dial, so as to indicate a less amount of superheat. 1f the pressure in both tubes increases or diminishes at the same time by a coincident i11- crease in the pressure and temperature of the steam in the superheat chamber, the pointer will be moved a distance corresponding to the diiierence between the oppositely acting forces, and in the direction urged by the greater; and where the increase or diminution of pressure in both tubes is the same, or rather such as to impart the same amount of movement to each of the pivot pins 19 and 19a, the linkage, if arranged as an equal sided parallelogram, will merely oscillate about the pivot 27, and the pointer will remain stationary.

As the dial is operated by clock work and is marked radially at intervals corresponding with the hours or other desired time periods of the day, the pointer will indicate not only the degrees of superheat set off upon the radial lines but also the time of the reading. And the marke-r, if adjusted to engage or contact with the face of the dial, will trace upon it, as it moves by clock Work, a continuous line which will record graphically the varying amount of superheat existing at. every moment` of the day.

It will be understood that we do not limit ourselves to the particular mechanism herein shown and described, for the same can be modified in various ways without departing from the principle of the invention, the scope of which is defined in the claims.

We claim as our invention:

1. 1n a superheat gage, the combination, with a chamber for superheated gas, lof a vpointer away from the center of the dial,

thermometric device inserted in the chamber, a pair of movable members connected one with the thermometric device and the other with the interior ot' the chamber, whereby said members are actuated independently, one by the heat and the other by the pressure ofl the therein contained gas, a dialcalibrated for degreesof superheat, and an indicator Working over the face of the dial, said movable members being operatively con-l nected With the indicator so as to give it a resultant movement ycorresponding to the amount of superheat in the gas.

2. In a diiierential gage, the combination, with a pointer, of a pair of sliding pivot pins, a pair of pressure-actuated devices arranged to be acted upon by separate sources of pressure and oppositely connected with said pivot-pins, respectively, and parallel motion linkage connecting said pivot-pins with each other and With the pointer.

3. In asuperheat gage, the combination, with a chamber for superheated gas, of a thermometric device inserted in the chamber, a pair of spring members connected one with the thermometric device and the other With the interior of the chamber, whereby said members are actuated independently, one by the heat and the other by the pressure of the therein contained gas, a dial calibrated for degrees of superheat, and an indicator Working over the face of the dial, said` springs being oppositely connected with the indicator so as to give the same aresultant movement, corresponding to the amount of superheat in the gas.

4. In a superheat gage, in combination, a dial calibrated for degrees of superheat, an indicator working over the face of the dial, a pair of spring tubes closed at their outer ends, one of the tubesbeing open at its inner end and the other tube beingclosed at its inner end and containing an expansible fluid, both of the inner tube-ends being adapted to be insertedinto a chamber of superheated gas, and the outer tube-ends being operatively connected vvith the indicator so as to impart to the same a resultant movement corresponding to the amount of superheat in the gas.

5. A superheat gage comprisingk a dial graduated in one ,direction for time periods andg in another direction for degrees of superheat, an indicator Working over the face of the dial, clockwork mechanism for moving the dial'so as to carry the time-period graduations successively past the indicator, `a chamber for superheated gas, a thermometric device insertedin said chamber, and a pair of movable members connected onewith the Vthermometric device and the other With the interior of the chamber, whereby said members are actuated independently, one by the heat and the other by the pressure of the therein contained gas, said movable members G. In a differential gage, the combination,

with a pointer, of tWo coil spring tubes closed at their outer or free ends and arranged for communication attheir inner ends With separate sources of fluid pressure, a pair of levers oppositely connected With the respective tubes, a pair of pivot-pins connected with the respective levers and guided to slide in parallelism, and linkage connecting the pivot-pinsand pivotally connected with the pointer, whereby the pointer Will be moved to an extent corresponding With the sum or difference of the movements of the tube-ends.

`7. In a gage of the class described, the y combination, with a pointer, of a pa-ir ot' spring tubes closed at their outer ends, one of the tubes being open at its inner end and the other tube terminating in a closed bulb, both of the inner tube-ends being adapted to be insertedo into a chamber of superheated gas, and means operatively connecting the outer ends of the tubes with the pointer so as to vgive the pointer a resultant movement' corresponding to the amount of superheat in the gas.

V8. In a gage of the class described, in combination, a pair of spring tubes closed at their' outer ends, one of the tubes being open at its inner end and the other tube terminating in a` closed bulb, both ot said inner tube-ends being adapted to be inserted into 100 la chamber of superheated gas, a dial calibrated for degrees of superheat, a pointerl Working over the face of. the dial, and parallel motion linkage oppositely connected with the outer ends of the tubes and interino-.105 diately connected .with the pointer for imparting to the pointer a resultant movement corresponding to the amount of superheat in the gas.

9. In a gage of the class described, 1n com- 110 bination, a rotary dial graduated radially .for degrees of superheat and circumferentially or time periods, a pivot-ally mounted pointer Working over the face of the dial, apair of spring tubes closed at their outer or acting ends, one otl the tubes being open at its inner end and the other tube terminating in a closed bulb, both of the inner tube ends being adapted to be insertedinto a chamber of superheated gas, and linkage voppositely connected With the outer ends of the tubes and intermediately connected with the pointer, for 'the purpose set forth.

10. In a gage of the class described, in combination, a dial graduated for degrees'125 of superheat, a pointer Working over the face of the dial, a pair of s'pring tubes closed atl 'their outer ends, one of the tubes being open at its inner end and the other tube terminating in a closed bulb, both of the inner tubej ends being adapted to be inserted into, a chamber of suporhent'ed gas, and means adjust-ably connected with the outer ends ofthe tubes and operating upon the pointer for giving the pointer a. resultant movement oorresponding to the amount of superheat in the gus. f

In testimony whereof We aHix our signatures in presence of two Witnesses.

THOMAS M. LOTHROP. GRANT D. BRADSHAW. Vitnesses v:

A. F. DREES, C. S. SEAVER, Jr. 

